Silica-based mesoporous materials have been employed as the support host for a suitably designed small octanuclear nickel(II) guest complex with a moderately anisotropic S = 4 ground spin state (D = 20.23 cm 21 ), which behaves as a single-molecule magnet at low temperature (T B = 3.0 K). Both unimodal MCM-41 and bimodal UVM-7 porous silica provide appropriate template conditions for the incorporation and aggregation of the Ni 8 complex precursor into larger complex aggregates, showing slow relaxation of the magnetization at higher blocking temperatures than the crystalline material. By playing with the initial complex vs. silica concentration, two series of samples with varying complex loading amounts have been obtained. The degree of aggregation varies, largely depending on the silica used, being higher for the bimodal UVM-7 silica series. The mesophasic and porous nature of the Ni 8 adsorbed silica samples has been verified from XRD and TEM images. N 2 adsorption-desorption isotherms show that incorporation initiates inside the small intra-particle mesopores while subsequent aggregation occurs at the external particle surface (close to the mesopore entrances). Both DC and AC magnetic susceptibility measurements have demonstrated the occurrence of such a unique silica-mediated surface aggregation process of cationic Ni 8 molecules into oligomeric [Ni 8 ] x aggregates of large spin values (S = 4x) and high blocking temperatures (T B = 4.5-10.5 K). The existence of a wide distribution of aggregates with different conformation and association degree (size distribution) and the presence of weak interactions between the aggregates leads to an exotic spin glass magnetic behavior for this family of host-guest hybrid nanocomposite materials.

Most valorization processes for biomass waste require dry raw material or at least a relatively low amount of residual humidity. In contrast, the hydrothermal carbonization (HTC) is a valorization process for lignocellulosic biomass which uses water as reaction medium. The product, hydrochar, can be used as dry solid fuel being the post-process drying procedure much more energy-efficient. Herein, three lignocellulosic biomass waste feedstocks, i.e. the organic fraction of municipal solid waste (OFMSW), orange peel waste (OPW) and the residues of a pepper plantation, were processed by HTC on a ton scale and the product evaluated as solid fuel in form of pellets for domestic use (EN ISO 17225). A critical property of the product is the ash content which has to be adjusted by post-treatment. The ash content was achieved to below the established limit by acid treatment with sulfuric acid. An implementation of the treatment into the pilot plant is straightforward.An organic liquid fraction was obtained as additional effluent in the pilot plant depending on the biomass feedstock. For instance, limonene in a mixture with other monoterpenes was separated when orange peel waste was processed, approximately 3 wt% of dry matter. It is further shown at laboratory scale that the monoterpene mixture can be directly used or can easily be transformed into para-cymene, a fragrance compound, by catalytic dehydrogenation. Therefore, the HTC process can be considered as a source for valuable apolar platform molecules derived from lignocellulosic biomass waste in addition to the production of hydrochar.2

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